I. Field of the Invention
This invention relates to a connecting method of printed substrates in which an optional printed substrate is connected with another printed substrate such as a multi-layer printed substrate.
II. Description of the Prior Art
Conventionally, surface-mount parts such as IC chips are mounted on a printed substrate in such a way that solder (cream solder) is coated on a connection pattern formed on a surface of the printed substrate, and on such formed surface, leads protruded from a main body of the surface-mount part are soldered by a reflow system, those of which are disclosed in Japanese Patent Application Laid Open No. Hei-3-227099 in 1991.
If the optional printed substrate is connected with the other printed substrate to produce in appearance one sheet of printed substrate, the relatively expensive multi-layer substrate is used only for the other printed substrate, a relatively inexpensive single-layer substrate can be used for the optional printed substrate, this produces an advantage in largely reducing cost.
In general, however, the printed substrates are opposingly positioned across the separator, then junctioned to each other by a fixture method (means) such as screws, and electrically connected by using a connector or a lead wire or the like, this separately requires constituent members including connectors and lead wires, and results in higher cost and lower reliability due to its complicated structure. In addition, uselessly occupied spaces increase resulting in a larger size of the printed substrate together with increased noise and loss when applied to a high-frequency circuit.